I unpacked the tar/zst archive again and it appears all the hard links are preserved in there. ls -li and file list comparison shows that all the files in private and public dirs are hard linked to the objects tree. Somehow some of them did become unlinked after I unpacked into the new server and I have yet to figure out what I did wrong. It is probably not snac at issue. I probably should restore from the tar archive, start snac again and watch it to see if it takes. Thanks for your help.